Candidates of the PDP led by Mufti Mohammed Saeed surged ahead in 30 of the 73 seats where early trends were available, officials said. The state assembly has 87 seats.
A total of 48.29 lakh votes are to be counted.
The BJP was ahead in 23 seats. The Congress led in six seats and the ruling National Conference in 13. One seat appeared to be going the way of a smaller party.
Most exit polls have predicted a hung assembly in Jammu and Kashmir, the country's only Muslim-majority state.
Minister of State in the Prime Minister's Office Jitendra Singh said: "This will be a turning point for BJP and for Jammu and Kashmir politics."
PDP leader and former chief minister Saeed was on the winning track in Anantnag.
So was Chief Minister Omar Abdullah in Sonawar and Deputy Chief Minister Tara Chand in Chhamb.